a(n) = 9*n^2-1.

Terms

a(0) =8a(1) =35a(2) =80a(3) =143a(4) =224a(5) =323a(6) =440a(7) =575a(8) =728a(9) =899a(10) =1088a(11) =1295a(12) =1520a(13) =1763a(14) =2024a(15) =2303a(16) =2600a(17) =2915a(18) =3248a(19) =3599a(20) =3968a(21) =4355a(22) =4760a(23) =5183a(24) =5624a(25) =6083a(26) =6560a(27) =7055a(28) =7568a(29) =8099